EFIDynoTuning Forum

Can't remember where I got it but the open loop enleanment calculation looks like this:

correction_value = FRCSFT * ACT + (1-FRCSFT) * ECT

What is FRCSFT? Can't find an explanation anywhere.

After waiting for warmer weather I tried it at 50% enrichment and 0% enrichment. Only difference is now the car does not fire up to ~1800rpm on initial start, otherwise symptoms are the same, cranks and kinda sorta tries to fire up but dies getting progressively worse as the plugs quickly flood and foul out.

The scaling gave me trouble when making injector slope adjustments in tunerpro so I gave up temporarily, but as I mentioned I drove ~60miles on this tune before this issue started, so it must be some component failure, bad contact, or bad ground, right? The MAF is matched to the 36# injectors.

I just noticed something in the logs - every single one of my logs starts with a TP_REL_CALC value of around -63, slowly rising to 0 over ~20 seconds. RATCH seems to reset to 275 with every power cycle and drop slowly. Is this a bad/out of adjustment TPS, or does it look normal? Could a negative TP_REL_CALC throw off a table lookup or cause some other undefined behavior? RATCH in blue, TP in green, TP_REL_CALC in purple, you can see for about the first 20 seconds RATCH is higher than TP, and again same pattern just before 100 sec.

With clean plugs the engine would start and idle (very rich, as expected) with MAF unplugged, so I swapped out for a new MAF sensor, no improvement. I did notice something else about the signal now (see attachment), this time MAFV curve does not track the shape of the RPM curve. MAFV stays flat while RPM rises and drops sharply - would expect both to be roughly the same shape, so maybe there's a bad connection between MAF and ECU? Also, MAF+ pin at connector reads 5.8V with sensor unplugged, not sure if that's far enough out of spec to cause a problem (should be 5V as I understand).

At this point I have done the following:
New MAF sensor
New ignition module
Swapped in old but working dizzy
new IAT sensor
Swapped in old but working coil (in case the problem was weak spark)
Verified MAF connector power voltage, input voltage, and ground
Verified fuel pressure during cranking (set at ~45PSI as recommended for the trickflow injectors)


Unless I'm missing something it looks like ECT sensor and ECU are the only components I haven't tried replacing yet, but this would be an odd failure for an ECU...However if the 5.8V MAF+ voltage is the problem then that would implicate the ECU...

In attached image, orange line is RPM, blue line is IMAF, note how IMAF levels out while RPM rises and falls.

Thanks for the response. Fuel pressure is good (adjustable regulator set at 45 PSI as per injector spec). Threw some parts at it, tried some adjustments, still no dice.

Turns out it isn't going lean, I pulled the plugs and they were all carbon fouled and soaked with gasoline. I'm guessing my wideband reads lean because the mixture is so rich that there's incomplete or no combustion (explains the thick white smoke that doesn't smell like coolant). But I think I found something interesting: in the attached log plots, engine fires up for a couple seconds, then dies (twice). You can see that as RPM (orange line) drops, MAFV (blue line) actually increases. Here are the RPM and MAFV values normalized to [0, 1]: And here are the raw values, MAFV voltage roughly in the range of [.6v, 1.1v] while RPM decays from ~1k to 0. FUELPW1 (not shown) tracks the MAFV voltage so the ECU is definitely dumping excessive fuel as if it thinks its lean: Does this look like a bad MAF signal, or are there circumstances where it makes sense for MAFV to go up while RPM drops?

TL;DR: after startup, in open loop, runs for a few seconds increasingly lean mixture to the point of nearly or totally dying. Standalone wideband and HEGO1 reading (in tunerpro) both confirm lean condition. Target lambse in tunerpro is rich. What constants/functions/tables are involved in final commanded fuel in open loop other than FN1362 (Base Fuel Table / WOT Multiplier)? Recently got worse, looking for values I can monitor in tunerpro to help diagnose.



351w with a 95 eec-iv MAF swap. Trying to diagnose a lean condition shortly after startup, confirmed on a WBO2 gauge. After cranking, engine will run for a few seconds with nominal AF on wideband, then slowly lean out to the point of dying - occasionally surging rich a few times first. This is happening in open loop - drives fine with good AF in closed loop but recently I can't get it to keep running at all as the starting lean out has gotten worse.

Monitoring in tunerpro with decipha_211230.adx, spk_lambse_calc rises to >1.20, LAMBSE1 goes from .48 to .68 - yet the engine sputters like its lean, and wideband shows >17 A/F. Now IIRC during open loop a number of inputs and corrections are disabled, E.G. HEGO, long and short term trim (?). Are there any values/functions/corrections applied to FN1362 that could cause the actual amount of injected fuel to be metered too low, but only in open loop? The injectors aren't dialed in but the fact that it has suddenly gotten worse after the last week has me wondering if some sensor is failing.

Base fuel table and example log attached, for anyone curious.

For anyone who might have a similar issue later, it turned out to be that I had the O2 sensor plugged into the wrong harness. Thanks for the help.

Not quite sure about how to adapt the fueling writeup to tunerpro, since the SP integral to the definition file. The default values from my ECU for AP** AHISL and SP** Global Fuel K-Constant give a DO NOT CHANGE - Scaling Percentage of 13.3171, but according to the writeup it should be closer to 19#/30?

So to modify the bin with the TFS injector values (HS=38.557, BPT=0.00001284, LS=38.557, SP:38.557/30 = 1.2853), I would:
1. set SP** Global Fuel K-Constant = 30
2. set SP** (WARNING) AHISL - Injector High Slope = 38.557 ? Or scale by SP to 30? Not sure as this param used to calculate the Scaling Percentage param.

3. set SP** ALOSL - Injector Low Slope to 38.557 scaled by SP = 30?
4. set SP** FUEL_BRKPT - Injector Breakpoint (2 of 2) to 0.00001284 scaled by SP = 9.6e-6?

And then would I need to rescale the remaining tables/params (maf curves, SARCHG, etc), or would tunerpro do that for me with this xdf?

I have TFS-89036 installed and set at 45PSI. I'm following the fueling page in the guide, I've attached a screenshot of the values read from the ECU before modification. Do the AHISL (255.996 lbs/hr) and ALOSL (286.184 lbs/hr) values make sense, or is there a possible mismatch between the adx/xdf and my ecu?

Also, just to confirm, SP**Global Fuel K-Constant is the value to set to 30, as per the guide?

I'm all set up and reading real time data, thanks again for the help. I can now confirm that the ECU does not command more than about 12deg SAFTOT at 2-3k RPM, and hangs around 4-5deg at 1500 RPM. I've attached two screenshots of the dashboard, one at idle and one at 22k rpm. Both tests conducted in park, engine warm. Does anything stand out?

One potential issue, HEGO values stay pegged near 0V regardless of RPM/throttle position/throttle movement, even when my wideband (not hooked to ECU) reads 12 or less. That would potentially cause ECU to pull timing, right? HEGO signal is good at wire, going to verify that it's on the right ECU pin shortly.

Great, thanks for the help. I've been using Binary Editor for logging, as I did not find the ADX file for VEX1. Is one available? Not sure about whether I can just dump all of the tables in the VEX1.xls file into one big CSV and import?

Alternatively, is it possible to apply the logging patch in Binary Editor? Didn't see it in the docs.